1. Field of the Invention
The present invention relates to a coupling socket for allowing a hole in the coupling socket to be communicated with a hole in its corresponding plug and a locking member of the socket to be engaged with a locking groove on the outer circumference of the plug when the socket and the plug are connected to each other.
2. Description of the Related Art
The coupling which allows the hole in its socket to be communicated with the hole in its plug and the locking member of its socket to be engaged with the locking groove on the outer circumference of its plug when socket and plug are connected to each other changes its structure depending upon gas, fluid or the like for which it is used, or pressures of these matters under which it is used. Therefore, various kinds of structures are employed by the coupling and even in the case of the coupling which is used under low pressure, the structure employed by it is not necessarily simple. In addition, steel balls are used for the locking member and the arrangement of those members which are related to the locking mechanism is complicated. This makes the cost of the coupling high.